It is now possible to track and identify a computer anywhere it goes on the Internet by using its clock skew as a method for fingerprinting it. Clock skew is what a computer thinks the time is as compared to other time-keeping with which it is interfacing. And when measured against other quantifiable processes when the computer is connected to the Internet, it can apparently provide a reliable fingerprint, unique and allowing it to be tracked across the Internet. Voila. The clock skew fingerprint.

The clock skew fingerprint is based on the work of University of California graduate student Tadayoshi Kohno, who explains that clock skew fingerprinting works by taking advantage of the fact that typically “each party in a TCP flow includes information about its perception of time in each outgoing packet. A fingerprinter can use the information contained within the TCP headers to estimate a device’s clock skew and thereby fingerprint a physical device.”

This, by the way, is all done without the knowledge or any cooperation from the owner… [Continued...]